Two posters on anole evolution presented at JMIH last weekend were honored with SSAR poster awards. Anthony Geneva, a PhD student at the University of Rochester took home the prize in the Evolution, Genetics, & Systematics category for his poster on “A Multi-locus Molecular Phylogeny of Distichoid Anoles.” Mingna Zhuang, an undergraduate researcher at UC Berkeley, won in the Ecology, Natural History, Distribution, & Behavior category for her poster on “Comparative Gliding Performance of Anolis carolinensis and Anolis sagrei.” Although not on anoles, it also bears noting that Daniel Scantlebury’s study of adaptive radiation in Sphaerodactylus – which has been inspired partly by work on Anolis – won the SSAR’s Henri Seibert Award for best student talk on Evolution/Systematics. Congrats to Anthony, Mingna, and Dan!
The Sunday night poster session at JMIH 2011 had a few more anole offerings. Melissa Moody from Iowa State reported on a laboratory experiment on the developmental and fitness consequences of varying Anolis sagrei egg incubation temperature and humidity. Anolis sagrei eggs seem relatively robust to the variation experienced during this experiment. Paul Cupp of Eastern Kentucky University asked whether ground skinks (Scincella lateralis) and green anoles (Anolis carolinensis) could detect chemical deposits from the Eastern Milk Snakes (Lampropeltis triangulum); he found evidence that the skinks could detect these deposits while the anoles could not. Finally, Mingna Zhuang discussed comparative gliding performance of Anolis carolinensis and Anolis sagrei. She found that A. carolinensis is a considerably better glider, perhaps due to the fact that it has a flatter gliding posture than A. sagrei.
Janson Jones is at it again. Having just driven about as cross-continent as you can get, from Alaska to the Florida Keys, he is now waxing eloquent on the lizards of that delightful island string. Today’s post is about introduced green iguanas, which apparently are everywhere and spreading, but yesterday he posted twice, on brown anoles (A. sagrei) and bark anoles (A. distichus) , with some keen observations on interactions between the two. Most notably, he’s noticed on multiple occasions that the larger browns chase off the the daintier barks.
postscript: Just as I hit the “post” button, Jones put up another of his own, with further observations on bark anoles and outlining what would make an excellent Ph.D. dissertation project. Plus, this intriguing observation:
“…the iPad of anoles in the Florida Keys. They’re right on the edge, living in the third space, transitory ground between the browns on the ground and the greens in the trees. They’re not iPhones, but they’re not desktops either. Right in the middle — and perhaps drawing business from both sides?”
American Society of Naturalists’ Young Investigator Award winner Dan Warner presented a marvelous synthesis of studies of how external influences affect phenotype and survival in eggs and offspring of lizards and turtles. Among other things, he has demonstrated
that some types of plasticity are adaptive: in temperature sensitive sex determining lizards, males are produced at temperatures at which the fitness of male offspring is greater than that of females, and vice-versa. Continue reading Evolution Meeting 2011: Environmental Effects on Offspring Growth and Survival
Staniel Cay is one of the quaint Caribbean backwaters, populated by yachtsmen, expats, scalawags, locals and…scientists. For more than 30 years, Tom Schoener, David Spiller and associates have worked here, producing a series of textbook studies on food web ecology (most recently here).
Having finished our work in Marsh Harbour, we have relocated to Staniel, marking a return for me after a 19 year absence. As our plane wended its way down the Exuma
chain, the memories of my previous visits and their results came flooding back. While a graduate student in the 80’s, I read Schoener and Schoener’s 1983 Nature paper reporting the results of introductions of brown anoles (A. sagrei) to very small islands (approx. the size of a baseball diamond) around Staniel Cay. S&S, noting that islands of this size do not normally harbor anoles, decided to introduce lizards to watch the populations wither away, and thus learn something about the process of extinction. But to their surprise, the populations did not go quietly into the night. Instead, they thrived and some downright exploded in numbers, one island going from 10 introduced lizards to 98 the next year. Continue reading Return to Staniel Cay
“Are you sure you don’t want to take a lizard pole?” – “No way, we’re on vacation, not field work”.
But once arrived on the lovely Yucatan Peninsula in Mexico I just couldn’t get any of the anoles perching on about every single palm tree to dewlap for me. I’d speculate about their dewlap colours – they did look like A. sagrei, but how could I be sure without flipping out their dewlap? And if I did, would it be red or orange, and how broad would the yellow margin be?
It was as if they were mocking me with their presence, knowing that I was pole-less. On the next trip to the local supermarket, however, I saw and immediately grabbed a small package that read: “Fish pen, as seen on TV.” It was a tiny telescopic fishing pole, complete with hooks, reel and line, that can clip to your shirt like a pen. For MXP 200 (ca. $20), I just had to buy it. Although I wouldn’t recommend to hunt any large or skittish lizards with it (it’s a short pole), it proved to be quite effective to satisfy any spontaneous dewlap-flipping cravings during vacation. Continue reading Gear review: the Fish Pen
A new, two-volume set on the conservation of Caribbean herps has just been published. More on that in a minute, but let’s cut to the important stuff. There’s a great summary of the record of anole introductions (discussed previously a number of times on Anole Annals, such as here, here, here and here) in an article by Bob Powell and others. Here’s what they have to say about anoles:
“Anoles (family Polychrotidae). Anoles are highly diverse (Losos, 2009), quite adaptable, and often function as human commensals. Many species in the region exploit buildings, ornamental plants, and the night-light niche (e.g., Henderson and Powell, 2001, 2009; Perry et al., 2008; Powell and Henderson, 2008). Some are colorful and available in the pet trade (e.g., Kraus, 2009), but nearly all introductions within our region were inadvertent and attributable to stowaways in cargo such as building materials and ornamental plants.
Anolis cristatellus is native to the Puerto Rico Bank and was the only anole that made the list of most successful colonizing species (Bomford et al., 2009). Continue reading Introduced Herps of the Caribbean
In his book, The Lizard Keeper’s Handbook (1997. Advanced Vivarium Stystems, Inc.), Philippe de Vosjoli explains at length how to select prey items of appropriate sizes to feed to pet lizards. I agree 100% with what he wrote. However, I must say that not all lizards apply these rules under natural conditions (I guess they were absent from class on the day that lesson was taught). Here are some photographs I took of brown anoles and Swinhoe’s tree lizards in my study area that preyed on prey items that most certainly did not fall within the ideal prey size categories.
1. An Anolis sagrei male with a large caterpillar.
2. An Anolis sagrei female with the remains of a grasshopper that she had had in her mouth when we captured her.
3. A Japalura swinhonis female that rushed in to grab a beetle grub that was exposed when we accidentally knocked over a dead betelnut palm (Areca catecha) in our study area.
4. A Japalura swinhonis male that captured an adult Clanis bilineata in the secondary forest in our study area.
And I believe that anyone who works with the brown anole (Anolis sagrei) would agree with me that these lizards can do some truly amazing things, as can be seen from the photos above. One of the most mind-boggling things I have found in the stomach contents of some of these lizards are centipedes. On one occasion I found a 43 mm long Chinese red-headed centipede (Scolopendra subspinipes mutilans) in the stomach of a brown anole male (SVL = 54 mm). Not only was the prey almost as long as the body length of the predator, but centipedes are venomous. It takes guts to take on such a meal!
In a recent post, AA mentioned Janson Jones’ (Dust Tracks on the Web) report on catching a magnificent knight anole. Turns out that Jones is not only a kindred spirit, but a keen observer and an excellent photographer. Over the course of the last few days, he has posted a series of stories of observations of Florida anoles that are worth checking out.
Just a few comments. In “Clash of the Anole Titans” (photo above), he tells of a territorial battle between two male green anoles. Ultimately, the fight concludes when one male loses his grip and falls to the ground. Those who study the functional capabilities of anoles are always surprised at the great sticking ability of the anole toepad, much greater than is needed to support the lizard’s body weight (anoles can hang from a single toe!). Perhaps this ability has evolved, not for every day living, but for exceptional circumstances, such as prolonged, hand-to-hand combat or hanging on to a mini-van. Continue reading Great Tales of Florida Anoles
For about a decade now, several researchers have used remarkably realistic looking robotic lizards to study lizard behavior. A pioneer in this approach—especially with regard to studying anoles—is Terry Ord, now at the University of New South Wales. You can see videos of his robotic lizards, as well as clips of a variety of anole species displaying, on the Terry Ord Channel on YouTube (or read about his most recent work here). As you’ll see, these robots are very realistic, both in terms of appearance and motion pattern—they bob, pushup, and extend their dewlap just like a real anole. In fact, even when the rubber body of the lizard hasn’t been attached, the underlying struts move in a clearly anole-like fashion. Bottom line, at a distance, I think most humans would be fooled by a displaying robo-anole. And lizards seem to be fooled, too, because they clearly respond by displaying and approaching the robot—check out the videos and/or Ord’s papers. Or read the recent paper by Partan et al., which demonstrates that A. sagrei responds more to a robot giving the typical signature display than to one presening a different display occasionally given by a lizard in the population.
Just like audio playbacks which revolutionized the study of bird vocal communication, robotic lizards provide the opportunity to rigorously examine lizard behavior in a controlled and replicated manner. Many different questions could be examined, but one of particular interest concerns how anoles distinguish conspecifics from heterospecifics. By altering the display pattern—the timing and amplitude of headbobs, pushups, and dewlap extensions—and by altering the color and pattern of the dewlap, researchers have the ability to understand species-recognition. In turn, such an understanding may provide critical insight into how new species arise, because speciation is the result of changes that lead individuals to no longer recognize each other as conspecifics.
In the West Indies and southeastern U.S., the enormous population size of anole species makes them an important component of the ecosystem. In the rainforest of Puerto Rico, for example, the three most common anole species consume an estimated 450,000 insects per hectare. The flip side of this abundance is that anoles—small, not very fast, presumably tasty—may be an important food source for many other species. Indeed, most West Indian snakes eat anoles and, collectively, anoles constitute more than 50% of the diet of West Indian snakes. Similarly, many types of birds will eat anoles at least occasionally (e.g., 40% of the species at one study site in Grenada were observed eating anoles), and some species eat them in large numbers. In addition to birds and snakes, anoles seem to be eaten by just about any flesh-eating animal (or plant) big enough to do so. Other documented predators include many types of lizards (including many instances of cannibalism), dogs, cats, mongooses, frogs, katydids, tarantulas, spiders, whip scorpions, and centipedes (see Lizards in an Evolutionary Tree for citations and further discussion).
Despite the ecosystem importance of anoles, and particularly of predation on them, there is still a lot we don’t know about who eats anoles, when and how. For this reason, field studies are needed, and everyone should be encouraged to document observations they make. For example, a recent post on the “Anolis Lizard” page on Facebook provided a link to a video of a crab eating an unfortunate A. agassizi (itself a remarkable and little known species from Malpelo Island in the Pacific). I am unaware of any previous evidence of crab predation on anoles, and scavenging can be ruled out because the poor lizard is still alive. This situation may be atypical, though, because Malpelo is essentially one big rock, and thus the anoles are always on the ground. Continue reading Nature’s Lunch Box
During a visit to New Orleans last month , I came across this little fellow.
He was about 2 feet up on some broad-leaved plants planted around a tree in Washington Park, at the corner of Frenchmen and Royal Streets in Faubourg Marigny, just east of the French Quarter. Here’s an overview of the Square looking east, taken from about where the lizard was found.
I was actually a little surprised to find carolinensis, rather than sagrei. Anolis sagrei is well known as a good colonizer, both natural and introduced, and is now known from Florida, Texas, Georgia, and Louisiana, with stragglers reported as far north as Virginia. I was once given a tiny baby anole that was caught on a windowsill in Cambridge, Massachusetts (!) that I believe was this species; it had probably arrived as an egg in the soil of a houseplant.